In order to improve wet handling, pneumatic tires are provided with grooves in their treads, wherein increased groove cross sections may increase the tire's drainage capacity. Unfortunately, grooves may negatively influence the tire's steering stability and grip. Indeed, during cornering, grooves of known tires may be subjected to buckling and tread portions laterally adjacent to these grooves may be raised from the road's surface such that they no longer contact the road.
In dry conditions, this phenomenon impairs the adherence contact between the road and the tire, and may result in a loss of control when making sudden maneuvers at high speed. In particular, typical tire grooves may have high stress concentrations and undergo buckling during heavy handling of a tire resulting in limited dry performances. Moreover, in wet conditions, the groove's cross sectional area may be reduced, thereby impeding its drainage capacity.
Document US 2013/0112325 A1 discloses a pneumatic tire with an asymmetric tread portion. The tread portion is provided with circumferentially extending grooves having tilted sidewalls. The outermost groove has sidewall cross sections or profiles with different tilts in respect of a line perpendicular to the tread. The other grooves show sidewall cross sections which are more tilted than the counterparts of the outermost groove. This arrangement is intended to maintain a safe cornering stability and also a low noise level. However, in particular cornering stability may still be improved, especially at high speed on a vehicle having a non-zero, positive camber angle.
It may be one object of the present invention to overcome at least one of the afore-mentioned disadvantages. Another object of the present invention may consist in increasing the cornering stability or stiffness of a pneumatic tire. Yet another object of the present invention may consist in providing enhanced dry and wet performances of high performance and ultra high performance tires. A further object of the invention may consist in improving the local stiffness of a tire's tread near the tire's main grooves during a cornering maneuver, preferably without significant trade-offs in wet handling.